Predicting temperature distribution of passively balanced battery module under realistic driving conditions through coupled equivalent circuit method and lumped heat dissipation method

Abstract

The current study intends to model a passively balanced battery module. The model provides scenario specific thermal predictions which can be used as input for designing and optimising Battery Thermal Management System (BTMS). The study includes the effects of module level passive balancing on thermal prediction and vice versa. The constituent cells used in the battery module are modelled by integrating Equivalent Circuit Model (ECM) in MATLAB Simulink and Computational Fluid Dynamics (CFD) simulations in COMSOL Multiphysics. The heat generation rate calculated in the MATLAB Simulink environment is used as input to COMSOL Multiphysics for temperature calculations. Successively, the average temperature of the cell is re-entered into ECM for calculation of the Equivalent Electric Circuit (EEC) parameters. The EEC parameters are SoC and temperature dependent. Therefore, the effect of temperature variation on Li-ion cell performance and heat generation is also considered. The Li-ion cell model is validated against experimental drive cycle data. The validated Li-ion cell model is used to create a passively balanced battery module with a 3S4P arrangement. The switching shunt resistor method is used for balancing circuit design. The modelled battery module is simulated with an actual drive cycle for the voltage, SoC, and thermal predictions.